Yes, WANDERER is a Scrabble word!

Letter values in Scrabble US: W 4, A 1, N 1, D 2, E 1, R 1, E 1, R 1.

Is it a valid word?

WANDERER is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

someone who leads a wandering unsettled life
a computer program that prowls the internet looking for publicly accessible resources that can be added to a database; the database can then be searched with a search engine

Also: bird of passage.